The present invention relates generally to heat sensitive warning devices, and particularly to such a device for indicating excessive temperatures in the wheel bearings of railroad cars.
Every year substantial losses are incurred by railroads by reason of bearing failure resulting in sometimes catastrophic accidents. Efforts to provide indicators for overheated car bearings have included both mechanical indicators as well as sophisticated arrangements utilizing infrared heat sensing equipment located adjacent the track. A number of mechanical type indicators rely on a fusible substance which melts in the presence of high temperatures to gravitationally release a visual signal of one sort or another. While several indicating devices have been proposed, to my knowledge none has found a high degree of acceptance. While infrared heat sensing equipment can detect overheated bearings a problem exists in identifying the car having the bearing problem and secondly, the expense occurred in such a system justifies its use only in high traffic areas. While various warning devices and other heat sensing equipment has been proposed the fact remains that each year brings substantial losses to various railroads by reason of accidents occurring which are ultimately attributable to bearing failure.